Sorry to break it to you, but at least some people consider RCS to be DOA in that respect.
"Text messaging used to be a cash cow for carriers, but with the advent of unlimited texting and the commoditization of carrier messaging, there's no clear revenue motivation for carriers to release RCS. The result is that the RCS rollout has amounted to nothing but false promises and delays. The carriers nixed a joint venture called the 'Cross-Carrier Messaging Initiative'¹ in April, pretty much killing any hopes that RCS will ever hit SMS-like ubiquity."²
¹ "Verizon, AT&T, and T-Mobile kill their cross-carrier RCS messaging plans" https://arstechnica.com/gadgets/2021/04/verizon-att-and-t-mo...
² https://arstechnica.com/gadgets/2021/06/google-enables-end-t...
We have that. It is called iMessage. It replaces SMS, has all the added features, and transparently "just works." You just need to upgrade your phone to one that has it.
Google should be asking Apple to release iMessage for Android, not this silly "green bubble" campaign.
I believe people have already been asking this for years, to no avail
Our goal should be to turn cell carriers into dumb data pipes. They have demonstrated repeatedly that trusting them with more is a bad idea.
I'm not sure about the messages themselves, but I wouldn't be surprised if Google has extra metadata and supports features that only work within the world of GMail and gracefully degrade in other clients—but, unlike IMAP, I haven't worked with that directly, so I'm not confident either way.
(Concrete example: GMail has additional integration with Google Calendar just like Outlook has integration with Outlook's calendar, but I'm not sure how that manifests at the protocol level.)
The "RCS" that Google implements does not follow the standards that have been around decades.
The interopability and push for RCS is a marketing exercise.